Megan,there is no legal requirement that a letter of mental status be provided for a plastic surgeon performing the surgery you wish to have.
However, there is also no legal requirement that the surgeon do such an operation from you without following his or her own guidelines. I would imagine most would see the request as prime facie eveidence of a mental problem in the requestor.
However, as tekla said LA, maybe NYC, or one of the larger metro areas in USA not in Texas or the Midwest or Southeast states. I'd try LA.
Nichole